The technology disclosed relates to domain name system (DNS) resolution of bare domain names of the form “myexample.com”. A bare domain name is also called zone apex or naked domain. In particular, bare domains are resolved by look-up of “A” records, per the Internet Engineering Task Force (IETF) standards for DNS resolution. Technology is disclosed that improves resolution of bare domains when used in conjunction with a content delivery network or cloud-based content provider (collectively referred to as CDNs).
DNS resolution is performed according to standards established by IETF. These standards were first established before the development of content delivery networks and content provider edge server technology.
DNS standards treat a bare domain name differently than a qualified name or a subdomain. For example, “google.com” is a bare domain name that links to an “A” record, while “www.google.com” is a subdomain that can link to either an “A” record or a canonical name (CNAME) record. An “A” record resolves directly to an IP address, while a CNAME record adds an abstraction layer that can resolve to another name for recursive resolution. Any subdomain that has a CNAME record is prohibited from having an “A” record or most any other record type. See “CNAME at the zone apex draft-sury-=dnsext-cname-at-apex-00” (Sury) (Aug. 18, 2010) Retrieved from the Internet: <URL: http://tools.ietf.org/id/draft-sury-dnsext-cname-at-apex-00.html> This creates a conflict that prevents an “A” record for a bare domain from coexisting with a CNAME or other abstraction layer record.
“A” records are not directly compatible with routing to CDN edge servers. For example, an “A” record for myexample.com cannot be mapped to the subdomain myexample.akami.com of a CDN. Mapping to a subdomain within a CDN domain would allow myexample.com to be resolved to the closest and most responsive of, for example, Akamai's 1900 data center networks worldwide. However, because myexample.com is a bare domain, it is resolved using an “A” record that specifies an IP address, without being translated to a subdomain within the CDN provider's domain zone. This is because the DNS standards do not provide a mechanism for mapping the bare domain to anything other than an IP address.
Managed DNS service providers have developed proprietary approaches to aliasing of bare domains. For instance, one managed DNS service provider provides a proprietary alias record scheme. Compare Hirose, “Naked Domain Redirection?” on AWS Forum (posted Dec. 6, 2010) Retrieved from the Internet: <URL: https://forums.aws.amazon.com/thread.jspa?threadID=55995>; with Amazon Route 53, “Creating Alias Resource Record Sets”, p. 54 in Developer Guide (API Version Apr. 1, 2013) Retrieved from the Internet: <URL: http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/CreatingAliasRRSets.html>. Using this approach, the bare domain myexample.com would be resolved by a provider's proprietary DNS server. The provider's DNS server receives a bare domain DNS request, looks up the proprietary alias record, and uses the proprietary mapping to return an IP address for a CDN (potentially cloud based resources, in Amazon's case.) That is, the proprietary alias record running on a proprietary DNS server causes non-standard behavior: the authoritative DNS server acts recursively, using a subdomain name in an alias record to recursively resolve what began as a bare domain DNS request. It ends up returning an IP address for a CDN.
It is desirable to provide new alternatives for resolving bare domains that connect a requestor using a bare domain name to a CDN or other cloud-based content source.